This invention relates generally to computers used in environments where temperature extremes are likely to be outside normal operating parameters. This invention relates particularly to protection of data stored in a computer used in an extreme environment such as a motor vehicle. Still more particularly, this invention relates to apparatus and methods for preventing a computer storage device from starting up if an environmental parameter is beyond its operational limit.
As computer technology has advanced, computer systems have begun finding use in non-traditional applications. One of these applications is on board vehicles, such as automobiles, where computers are used for everything from engine monitoring to computer-aided dispatching. As the data contained in these computers becomes more vital, it becomes more and more critical to safeguard this data. Computers used in vehicle environments must contend with extremes in temperature that are outside normal operating parameters. These extremes in temperature can cause the computer system to malfunction and suffer failures ranging from component damage to loss of data. One of the most sensitive components in a typical computer system is the hard disk, which unfortunately is also one of the most critical components since it holds all data for the computer system. The data can be many times more valuable than the computer system hardware.
The prior art includes devices for protecting central processing units, cache memories and associated integrated circuits. However, the prior art fails to provide protection to the main data storage component, such as a hard disk drive, of a computer system used in an extreme environment such as a motor vehicle.
U.S. Pat. No. 5,623,594, which issued Apr. 22, 1997 to Swamy is directed to a system for monitoring the temperature of a heat-producing electronic device such as a microprocessor. The temperature monitoring apparatus comprises a thermistor embedded in the circuit board in which the microprocessor is mounted. The thermistor is formed of an electrically conductive trace 140 that has a temperature-dependent property. Circuitry is connected to the thermistor to measure the electrical property and produce a warning signal if the temperature becomes too high.
U.S. Pat. No. 5,598,395, which issued Jan. 28, 1997 to Watanabe is directed to a system for preventing data loss in a cache memory when the temperature of an optical recording medium (magneto-optical disk) is abnormal. At normal operating temperatures a write cache memory temporally stores information to be stored on the disk. The temperature of the disk is monitored by a temperature sensor and a microprocessor. If the temperature is too high, then the microprocessor disables the write cache memory.
U.S. Pat. No. 5,590,061, which issued Hollowell, II et al. is directed to thermal management in a computer system. A temperature sensor and microcontroller monitor the system temperature. If the temperature is too high, then power cycling is performed on selected integrated circuits to lower their duty cycles until the temperature is within a selected limit.
U.S. Pat. No. 5,477,417 which issued Dec. 19, 1995 to Ohmori discloses an electronic device such as a computer CPU that includes a thermistor for detecting temperature, logic circuitry for deciding whether the temperature is too high, a cooling system and an alarm unit.